Efforts to define marriage in the Iowa state constitution failed Thursday after one of the bill’s sponsors challenged the authority of the Senate Majority Leader.

A Thursday morning motion by Republican Sen. Kent Sorenson to allow a vote on a constitutional ban of same-sex marriage was defeated 26-24 along party lines. Sorenson attempted to call up the resolution even though doing so would mean breaking state Senate rules.

Democrats registered their frustration in the vote. The vote was split down partisan lines with Republicans voting for the motion and Democrats against it.

Prior to the vote, state Senate Majority Leader Mike Gronstal (D) vowed to never allow such an amendment to come up for debate.

Gronstal had scheduled another resolution to vote on in the morning instead of Senate Joint Resolution 8, which defines marriage between one man and one woman as the only legal union recognized in Iowa.

At 7:30 a.m., Sorenson asked for all state Senate members to allow Resolution 8 to be considered on the floor. Sorenson’s motion went against Gronstal’s authority, thus violating Senate rules.

Senate President Jack Kibbie (D) initially denied Sorenson’s request, but later allowed Senate members to vote to upset Gronstal’s order.

Gronstal alleged that Sorenson’s motive was set on undermining his authority rather that defining marriage in the state’s constitution.

“It is not a vote on the constitutional vote, but I understand that people can lie and say it is,” Gronstal said.

However, Sorenson maintains that his true focus was on preserving families. In a Focus on the Family Action article, he identified traditional marriage as the key issue that led him to run against incumbent Mark Davitt (D).

“This is a pivotal issue. You have to communicate about it with respect, but don’t back down,” he told the publication about his fight for tradition marriage.

Today, Sorenson didn’t back down despite Gronstal’s opposition, but instead tried to power the bill through.

Prior to today’s vote, the traditional marriage bill had a chance at being successful. The current resolution was sponsored by all 24 Republican state senators, and five Democrats supported the same-sex marriage ban in a February 2010 petition.

Yet despite today’s failed Senate vote, Resolution 8 has found another audience in the state House. The Iowa state House has already passed a same-sex marriage ban and will be holding a public hearing to discuss the possible amendment on Monday.

The state Senate needs to pass traditional marriage legislation this year and again in 2013 in order for it to gain a spot on the ballot for a popular vote.